a)

$-5\cdot 30:\left(-6\right)=-150:\left(-6\right)=150:6$

Wykonujemy dzielenie sposobem pisemnym:

$\begin{array}{l}\underline{25}\\ 150:6\\ \underline{-12}\\ 30\\ \underline{-30}\\ =\end{array}$

Wobec tego

$150:6=25$

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b)

$$\begin{gathered} 2\frac{1}{4}:\left(-0,5\right):\left(-3\frac{3}{8}\right)=2\frac{1}{4}:\left(-\frac{1}{2}\right):\left(-\frac{27}{8}\right)= \\ =\frac{9}{4}\cdot \left(-\frac{2}{1}\right):\left(-\frac{27}{8}\right)=-\frac{18}{4}\cdot \left(-\frac{8}{27}\right)=\frac{{\cancel{18}}^2}{{\cancel{4}}_1}\cdot \frac{{\cancel{8}}^2}{{\cancel{27}}_3}= \\ =\frac{2}{1}\cdot \frac{2}{3}=\frac{4}{3}=1\frac{1}{3} \end{gathered}$$

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c)

$$\begin{gathered} -3\frac{1}{5}\cdot \left(-1\frac{1}{3}\right)\cdot \left(-15\right)=-\frac{16}{5}\cdot \left(-\frac{4}{3}\right)\cdot \left(-\frac{15}{1}\right)= \\ =\frac{64}{15}\cdot \left(-\frac{15}{1}\right)=-\frac{64\cdot {\cancel{15}}^1}{{\cancel{15}}_1\cdot 1}=-64 \end{gathered}$$